Washington Closure Hanford - Projects

Reactor Interim Safe Storage Project

The Reactor Interim Safe Storage Project is responsible for placing Hanford’s remaining retired plutonium production reactors into interim safe storage and providing surveillance and maintenance activities of inactive facilities.

Interim safe storage (ISS), or “cocooning,” is the process of demolishing all but the shield wal ls surrounding the reactor core, removing or stabilizing all loose contamination within the facility, and placing a new roof on the remaining structure. A single doorway in the structure is installed to provide access for surveillance and maintenance work. This doorway is welded shut, and all other openings in the shield walls are sealed to prevent intrusions and the release of radioactive materials. The facility is inspected every five years and remotely monitored at all times for changes in moisture and temperature.

The reactor core will remain in ISS for up to 75 years. The time is needed for the U.S. Department of Energy, regulators and other stakeholders to determine the final disposal method and to allow the high radiation levels in the reactor cores to decay to more manageable levels .

The River Corridor Cleanup Project completed placing H Reactor in ISS. The project’s current work scope includes cocooning K East and K West reactors in 2011, followed by N Reactor in 2012. B Reactor is being studied to determine if it will be preserved as a historical site or placed in ISS.